Work vehicles, such as a motor grader, can be used in construction and maintenance for creating a flat surface. When paving a road, a motor grader can be used to prepare a base foundation to create a wide flat surface for asphalt to be placed on. A motor grader can include two or more axles, with an engine and cab disposed above the axles at the rear end of the vehicle and another axle disposed at the front end of the vehicle. A blade is attached to the vehicle between the front axle and rear axle.
The present disclosure is not exclusively directed to a motor grader, but rather can extend to other powered vehicles as well. For exemplary and illustrative purposes, however, the present disclosure will focus on a motor grader. In FIG. 1, for example, a conventional motor grader 100, such as the 772G Motor Grader manufactured and sold by Deere & Company, includes front and rear frames 102 and 104, respectively, with the front frame 102 being supported on a pair of front wheels 106, and with the rear frame 104 being supported on right and left tandem sets of rear wheels 108. An operator cab 110 is mounted on an upwardly and forwardly inclined rear region 112 of the front frame 102 and contains various controls for the motor grader 100 disposed so as to be within the reach of a seated or standing operator, these controls including a steering wheel 114 and a lever assembly 116. An engine 118 is mounted on the rear frame 104 and supplies power for all driven components of the motor grader 100. The engine 118, for example, can be configured to drive a transmission (not shown), which is coupled for driving the rear wheels 108 at various selected speeds and either in forward or reverse modes. A hydrostatic front wheel assist transmission (not shown) may be selectively engaged to power the front wheels 106, in a manner known in the art.
Mounted to a front location of the front frame 102 is a drawbar 120, having a forward end universally connected to the front frame 102 by a ball and socket arrangement 122 and having opposite right and left rear regions suspended from an elevated central section 124 of the front frame 102 by right and left lift linkage arrangements including right and left extensible and retractable hydraulic actuators 126 and 128, respectively. A side shift linkage arrangement is coupled between the elevated frame section 124 and a rear location of the drawbar 120 and includes an extensible and retractable side swing hydraulic actuator 130. A blade 132 is coupled to the front frame 102 and powered by a variable displacement circle drive motor 134.
Referring to FIG. 2, a front axle 200 of the conventional motor grader 100 is shown in greater detail. The front axle 200 includes a first side 202 and second side 204 to which front wheels 106 are coupled. A portion 206 of the front frame 102 is shown in which the first side 202 and second side 204 each include a final drive assembly 208. In this conventional grader, a hydraulic motor (not shown) is disposed in the final drive assembly 208 to drive the corresponding front wheel. In other words, a hydraulic motor (not shown) is mounted at the first end 202 and second end 204 of the front axis 200. A wiring and hydraulic hose bundle 218 is coupled to each hydraulic motor and passes through the front frame 102 at different locations. The bundle 218 also attaches to different portions of the vehicle.
To achieve complete motion, a lean bar 210 is coupled to the front frame 102 and lean castings 214. A steering casting 212 is also disposed at each end of the front axle 200 to allow the front wheels 106 to steer about a steer pivot. A guard 216 is also provided at each end adjacent the final drive assembly 208. The configuration of the front axle 200 is such that sufficient clearance is provided between a ground surface and the axis 200 to aid with vehicle performance.
New technology, however, is being introduced to convert a conventional motor grader into an electric drive motor grader. This is not exclusive to motor graders, but rather other powered vehicles are being converted to electric drive as well. Previous attempts to convert a hydrostatic system to an electric drive system, particularly with respect to a motor grader, require the wheel hub and final drive assembly of the grader to be reconfigured to accommodate an electric motor. This is the result of the electric motor being larger in size (i.e., diameter and width) compared to a hydraulic motor. Thus, packaging the electric motor within a conventional final drive assembly is problematic due to space constraints.
A need therefore exists to provide a reconfigured package of a wheel hub of a front axle that includes an electric motor and that satisfies space constraints without changing the design of the wheel hub and castings of the front axle. It is further desirable to provide a package that achieves complete vehicle performance, including the ability to achieve desired rotation about the lean axis and steering axis through a full range of angles.